The use of an electric pressure rice cooker has been generalized in which food such as rice is generally accommodated in an inner pot and the inner pot is stably placed inside a main body so that the bottom surface of the inner pot tightly contacts a heat plate provided inside the main body and the inside of the inner pot is heated to a high temperature and high pressure state by the heat plate, thus cooking the food.
These electric pressure rice cookers can be divided into direction heating ones and induced heating ones according to heating methods.
In the direct heating electric pressure rice cooker, a heater coil installed on the bottom portion and external side surface of the inner pot is heated by receiving power, thus directly heating the inner pot for cooking and keeping warmth.
In the induced heating electric pressure rice cooker, an induction coil which receives power and generates an induced current is provided as a heat source member and the inner pot is made of a material which can provide heat by the induced current for cooking and keeping warmth.
As described above, the direct heating electric pressure rice cookers and the induced heating electric pressure rice cookers are different from each other. However, in their structures, only some elements forming the inside of the main body case are different from each other and the rest elements including the covers are the same.
Each of the direct heating electric pressure rice cookers and the induced heating electric pressure rice cookers is generally formed with a main body case 1, an inner pot 70 which is stably placed inside the main body case 1, and a cover 3 which is hinge-coupled to the top portion of the main body case 1.
The main body case 1 includes a variety of electric devices for heating an inner pot 70 and a support plate 5 which supports the inner pot 70.
Here, the inner pot 70 has a cylindrical receiving space 71 for receiving grains, and a plurality of coupling flanges 72 formed along the outer periphery of the top end of receiving space 71.
The cover 3 is formed with an outer cover 10 for hinge-coupling to the main body case 1, a locking unit 20 which is operated by a handle 21 coupled to a handle coupling groove 13 of the outer cover 10, an inner cover 30 which is coupled to the bottom portion of the outer cover 10 and guides the operation of the locking unit 20, a locking ring 40 which is coupled to the bottom portion of the inner cover 30 and is controlled by the locking unit 20, a top portion heating plate 50 which is coupled to a handle axis 22 at the bottom portion of the locking ring 40 and supports the locking ring 40 in a rotatable state, and a packing 60 which is inserted into a packing groove 52 formed on the bottom surface of the top portion heating plate 50 to maintain a tight seal of the inner pot 70.
The outer cover 10 includes a hinge portion 11 which is formed on the end of the back surface so as to be coupled to the main body case 1, a steam discharge portion which is formed on the back side of the top surface so as to discharge high-pressure steam, a handle coupling groove which is formed on the front side of the top surface so as to couple the handle 21, and an opening button 14 which is elastically formed on the end of the front surface so as to open the cover 3 from the main body case 1.
The locking unit 20 is formed with a handle 21 which is coupled to the handle coupling groove 13 of the outer cover 10, the handle axis 22 which is formed as a bottom portion of the handle 21 in a predetermined length, a top portion washer 23 and a bottom portion washer 24 to be placed on the handle axis 22, and an arm member 25 which is coupled to the handle axis 22 by the top portion washer 23 and bottom portion washer 24.
Here, the arm member 25 is made by twice bending a plate each time at a right angle, and an axis groove 25A formed on one side end is coupled to the handle axis 22 and a coupling protrusion 41 of the locking ring 40 is coupled to a protrusion groove 25B formed on the other side end of the arm member 25.
Formed on the top end surface of the inner cover 30 are a protrusion groove portion 31 supporting the handle axis 22 to which the arm member 25 is coupled, a pipe penetration groove 32 into which a solenoid valve pipe (not shown) and pressure pendulum valve pipe (not shown) penetrate, and a guide groove 33 into which the protrusion unit 41 of the locking ring 40 is inserted and rotates in a predetermined angle.
The locking ring 40 is formed in a circular ring shape having a flange on each of the top side end surface and the bottom side end surface and an open inner side surface. The locking ring 40 has a plurality of coupling grooves 42 on the inner circumferential surface of the bottom end portion with the flange corresponding to the coupling flange 72 of the inner pot 70, and a protrusion portion 41 on one location of the top end portion having the flange on the top end surface.
On a plate having a recess with a predetermined depth, the top portion heating plate 50 has an axis fixing portion 51 formed to be coupled with the handle axis 22, and a packing groove 52 formed on the peripheral portion of the bottom surface to allow the packing 60 to be inserted into.
Here, the top portion heating plate 50 performs a role of a shutter to maintain a tight seal of the inner pot 70.
The assembly process of the electric rice pressure cooker formed as described above according to the prior art will now be explained.
First, the outer cover 10 is hinge-coupled to the main body case 1.
Then, the handle 21 is coupled to the handle coupling groove 13 formed on the outer cover 10. On the handle axis 22 penetrating the outer cover 10, the top portion washer 23, the arm member 25, and the bottom portion washer 24 are coupled in order.
Then, the inner cover 30 is coupled. The solenoid value pipe (not shown) and the pressure pendulum value pipe (not shown), and the handle axis 22 are coupled with and penetrate corresponding to the pipe penetration groove 32 and the protrusion groove portion 31, respectively.
Then, when the locking ring 40 is coupled, the protrusion portion 41 is made to penetrate the guide groove 33 of the inner cover 30 and to be inserted into the protrusion groove 25B of the arm member 25.
Then, the handle axis 22 is coupled to the axis fixing portion 51 formed on the top portion heating plate 50.
Here, the axis fixing portion 51 and the handle axis 22 are coupled in order for the handle axis 22 to rotate.
Finally, to the packing groove 52 formed on the bottom portion of the top portion heating plate 50 the packing 60 is coupled.
Here, the operation of the prior art having the assembly process as described above will now be explained.
If the cover 3 formed by the assembly process is closed, the coupling groove 42 of the locking ring 40 and the coupling flange 72 of the inner pot 70 do not interfere each other. This state is also a state in which the cover 3 can be freely opened or closed and a state for keeping warmth of already cooked rice.
Meanwhile, when cooking is performed, the locking unit 20 which can stand a high temperature pressure occurring in the cooking is required. In an operation of the locking unit 20 according to this, if the handle 21 coupled to the top portion of the outer cover 10 is rotated in a predetermined angle in the locking direction, the arm member 25 coupled to the handle axis 22 rotates, and if the protrusion portion 41 of the locking ring 40 inserted into the protrusion groove 25B formed on the other end of the arm member 25 is rotated along the guide groove 33, the locking ring 40 rotates as if it wraps the outer circumference of the inner pot 70. If the coupling flange 72 of the inner pot 70 except the coupling groove 42 of the locking ring 40 is completely getting in the locking unit 43, the rotation is finished and the locking unit 20 can fully stand the pressure in a high temperature and high pressure cooking.
After finishing the cooking, the locking state can be simply released in a reverse order of the method described above.
The rice pressure cooker according to the prior art has a packing made of a rubber material and provided on the bottom portion of the top portion heating plate in order to prevent steam occurring in the cooking process from being discharged to the outside. However, this packing is made of a rubber material, and thus can be easily worn out in the repetitive opening and closing of the cover. Due to this wearing, the maintenance cost caused by replacing the packing increases.
Also, steam occurring from the food being cooked contacts the packing and changes into water drops to fall on the food. A packing used long time and worn is itself a pollutant and steam contacting this can also be contaminated. In particular, a synthetic resin material such as a rubber used as a packing can generate environmental hormone and also in the aspect of health, it is not desirable.